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Abstract:

In order to produce molded foam parts from foam systems, such as soft,
semi-hard and integral foam, foaming molds are typically used, which are
produced from different base materials, depending on the intended purpose
and required output or service life. Molds for producing molded foam
parts are produced from steel or aluminum. A negative or undesirable
property during the production of molded foam parts is that the foam
adheres to the foaming molds and can often only be removed mechanically.
In order to prevent this, the invention proposes a mold insert for a
molded part mold, comprising a cavity, wherein the mold insert can be
arranged on the molded part mold such that a volume-reduced cavity is
formed in the arranged state and the mold insert contributes to creating
the shape of the material.

Claims:

1. A mold insert for a metallic molded part mold, more specifically for a
foam or galvano-mold, with an upper part and a matching lower part, with
a cavity, more specifically a hollow, the molded part mold impressing a
shape onto a material, more specifically a foam introduced into the
cavity, wherein the mold insert is an injection-molded part which is
adapted to be disposed without a release agent onto the surface of the
molded part mold, the material thickness of the mold insert amounting to
between 0.8 mm and 8 mm, so that in the disposed state a correspondingly
volume-reduced cavity is formed and the mold insert contributes to
impressing a shape onto the material inside the volume-reduced cavity,
more specifically on its entire surface.

2. The mold insert according to claim 1, wherein a surface of the mold
insert matching the volume-reduced cavity has a slight or no interfacial
tension.

3. The mold insert according to claim 1, wherein the surface of the mold
insert matching the volume-reduced cavity is coated.

4. The mold insert according to claim 1, wherein the surface of the mold
insert matching the volume-reduced cavity is formed by a plastic
material.

5. The mold insert according to claim 1, wherein the surface of the mold
insert matching the volume-reduced cavity is formed by a polyolefin, more
specifically a polyethylene.

6. The mold insert according to claim 1, further comprising a temperature
conducting element.

7. The mold insert according to claim 1, wherein the material thickness
of the mold insert amounts to approximately 2.5 mm.

8. The mold insert according to claim 1, further comprising a fastening
element, which allows a detachable firm connection with the molded part
mold.

9. The mold insert according to claim 1, further comprising a support
structure.

10. The mold insert according to claim 9, wherein the support structure
has hollow spaces.

11. The mold insert according to claim 1, wherein it is formed by
assembled partial mold inserts.

12. The mold insert according to claim 11, wherein the partial mold
inserts have connection elements.

13. A device for manufacturing a molded part with a molded part mold with
a cavity which impresses a shape onto an introduced material, wherein a
mold insert for a metallic molded part mold, more specifically for a foam
or galvano-mold, with an upper part and a matching lower part, with a
cavity, more specifically a hollow, the molded part mold impressing a
shape onto a material, more specifically a foam introduced into the
cavity, wherein the mold insert is an injection-molded part which is
adapted to be disposed without a release agent onto the surface of the
molded part mold, the material thickness of the mold insert amounting to
between 0.8 mm and 8 mm, so that in the disposed state a correspondingly
volume-reduced cavity is formed and the mold insert contributes to
impressing a shape onto the material inside the volume-reduced cavity,
more specifically on its entire surface, said mold insert is adapted to
be disposed without release agent in the molded part mold, whereby a
volume-reduced cavity is formed which impresses a shape onto a material
introduced into the volume-reduced cavity, which has a reduced volume as
compared to when a material is introduced into the cavity without a
molded part.

14. The device according to claim 13, wherein the volume-reduced cavity
forms a shape of the molded part to be manufactured, the size of the
cavity formed by the molded part mold being increased by the thickness of
the material of the mold insert.

15. The device according to claim 13, wherein the molded part mold has a
matching receptacle for the fastening element.

16. The device according to claim 13, wherein the molded part mold is
made of a metal, more specifically stainless steel, steel, aluminum,
and/or magnesium, or an alloy.

17. The device according to claim 13, wherein the molded part mold has an
upper part and a lower part.

18. A method for manufacturing a molded foam part, the method including
the following steps: introducing a mold insert for a metallic molded part
mold, more specifically for a foam or galvano-mold, with an upper part
and a matching lower part, with a cavity, more specifically a hollow, the
molded part mold impressing a shape onto a material, more specifically a
foam introduced into the cavity, wherein the mold insert is an
injection-molded part which is adapted to be disposed without a release
agent onto the surface of the molded part mold, the material thickness of
the mold insert amounting to between 0.8 mm and 8 mm, so that in the
disposed state a correspondingly volume-reduced cavity is formed and the
mold insert contributes to impressing a shape onto the material inside
the volume-reduced cavity, more specifically on its entire surface
without a release agent into the molded part mold of a device for
manufacturing a molded part with a molded part mold with a cavity which
impresses a shape onto an introduced material, wherein said mold insert
is adapted to be disposed without release agent in the molded part mold,
whereby a volume-reduced cavity is formed which impresses a shape onto a
material introduced into the volume-reduced cavity, which has a reduced
volume as compared to when a material is introduced into the cavity
without a molded part, injecting a moldable material, more specifically a
foam into the volume-reduced cavity, so that the volume-reduced cavity
impresses the shape of the molded part onto the material in such a manner
that a molded part is formed, demolding the molded part, and removing the
mold insert from the molded part mold.

19. The method according to claim 18, wherein other molded parts are
manufactured before removing the mold insert.

20. The method according to claim 18, further comprising a coating layer,
which is impressed onto the molded part during manufacture, is applied to
the mold insert before injecting the moldable material.

21. The method according to claim 18, further comprising introducing a
molded part support before injecting the moldable material into the
cavity or the volume-reduced cavity.

22. The method according to claim 18, further comprising replacing said
molded insert with another mold insert after removing the molded insert
from said molded part mold.

23. The method according to claim 18, wherein said another mold insert is
a previously used molded insert which has been cleaned and reused.

24. A molded foam part which is manufactured with a device for
manufacturing a molded part with a molded part mold with a cavity which
impresses a shape onto an introduced material, wherein a mold insert for
a metallic molded part mold, more specifically for a foam or
galvano-mold, with an upper part and a matching lower part, with a
cavity, more specifically a hollow, the molded part mold impressing a
shape onto a material, more specifically a foam introduced into the
cavity, wherein the mold insert is an injection-molded part which is
adapted to be disposed without a release agent onto the surface of the
molded part mold, the material thickness of the mold insert amounting to
between 0.8 mm and 8 mm, so that in the disposed state a correspondingly
volume-reduced cavity is formed and the mold insert contributes to
impressing a shape onto the material inside the volume-reduced cavity,
more specifically on its entire surface, said mold insert is adapted to
be disposed without release agent in the molded part mold, whereby a
volume-reduced cavity is formed which impresses a shape onto a material
introduced into the volume-reduced cavity, which has a reduced volume as
compared to when a material is introduced into the cavity without a
molded part; and/or according to a method for manufacturing a molded foam
part, the method including the following steps: introducing a mold insert
for a metallic molded part mold, more specifically for a foam or
galvano-mold, with an upper part and a matching lower part, with a
cavity, molded part mold impressing a shape onto a material, more
specifically a foam introduced into the cavity, wherein the mold insert
is an injection-molded part which is adapted to be disposed without a
release agent onto the surface of the molded part mold, the material
thickness of the mold insert amounting to between 0.8 mm and 8 mm, so
that in the disposed state a correspondingly volume-reduced cavity is
formed and the mold insert contributes to impressing a shape onto the
material inside the volume-reduced cavity, more specifically on its
entire surface without a release agent into the molded part mold of a
device for manufacturing a molded part with a molded part mold with a
cavity which impresses a shape onto an introduced material, wherein said
mold insert is adapted to be disposed without release agent in the molded
part mold, whereby a volume-reduced cavity is formed which impresses a
shape onto a material introduced into the volume-reduced cavity, which
has a reduced volume as compared to when a material is introduced into
the cavity without a molded part, injecting a moldable material, more
specifically a foam into the volume-reduced cavity, so that the
volume-reduced cavity impresses the shape of the molded part onto the
material in such a manner that a molded part is formed, demolding the
molded part, and removing the mold insert from the molded part mold.

Description:

[0001] The invention relates to a molded insert for a molded part mold,
more specifically a foam mold or galvano-mold, with an upper part and a
corresponding lower part, with a cavity, more specifically a hollow,
wherein the molded part mold creates a shape of a material, more
specifically a foam, that is introduced in the cavity. The invention
furthermore relates to a method for manufacturing a molded part and to a
molded part.

[0002] In order to manufacture molded foam parts from foam systems, such
as soft, semi-hard, hard and integral foam, foaming molds are typically
used, which are manufactured from different base materials, depending on
the intended use and required output or service life. Plastic material,
plastic casting resins or plastic plates are used for instance for
prototype or pre-series molds, whereas molds made of aluminum and/or
steel are used for production runs, respectively for production of great
quantities and complex parts.

[0003] These forms mostly consist of a lower shell and an upper shell
which are connected by lateral hinges. When closed, both "halves" form a
desired hollow space which is also called a cavity and which forms the
required molded part.

[0004] Slides and inserts or the like, which are inserted and actuated
manually, semi automatically and automatically, are used for demolding
"undercuts", ribs and the like. When the form is open and/or closed, a
prepared foam system is introduced into the cavity by means of a gating
system via a mixing head.

[0005] A negative or undesirable property of the aforementioned systems is
that the foam adheres to the aluminum or steel of the foaming molds and
can often only be removed mechanically.

[0006] In order not to damage the parts during demolding or to be able to
remove them intact, diverse release agents are used. These release agents
prevent an "adhesion" of the foam parts to the surface of the molds.
Wax-based release agents, which are liquefied by means of solvents in
order to be applied by means of a spray pistol or a brush, are mostly
used.

[0007] These release agents must be applied before each cycle. In doing so
the solvent evaporates and the wax leaves a relatively thin layer on the
surface of the mold.

[0008] This is an independent process which must be stable in order to
ensure an unchanging quality of the parts. The release agents are usually
applied manually at the foaming plant by a worker by means of a spray
pistol and the produced spray and release agent vapors must be aspirated.

[0009] Due to the repeated addition of the release layer, a thickening wax
layer forms more specifically on the smaller radiuses or on the ribs,
which must be regularly removed.

[0010] The application of the release layer as well as the regular removal
of the wax residue represents a great time and cost expenditure,
associated with a repeated interruption of the production process.

[0011] A thin release layer also remains on the molded parts themselves.
This layer is only unproblematic when the part does not have to be
processed any further, i.e. when it is a finished part.

[0012] However, should the foam parts be subsequently laminated, this
layer of release agent residue makes it more difficult to glue the
laminating material onto the foam. The lamination is carried out for
instance by means of a leather or a foil. Thus, the foam part must be
cleaned before lamination.

[0013] The described release agents are also used in the manufacture of
spray skin or deep-drawn foil. So-called galvano-molds are frequently
used for manufacturing spray skins and deep-drawn foils. Surfaces for
door coverings, instrument panels or center consoles for instance are
manufactured by means of these galvano-molds.

[0014] Two-part polyurethane systems for instance are sprayed onto these
galvano-molds. A skin is thereby formed, the thickness of which varies
depending on the incorporated quantity and which is removed from the mold
after a corresponding reaction time. As explained above, release agents,
which are added either manually or automatically, must be used in order
to be able to demold or remove the produced skin.

[0015] The spray skins thus manufactured are frequently underfoamed with a
support resulting in more complex components. To this end, it is also
necessary to ensure that the spray skin is freed of any release agents.

[0016] Another disadvantage is that galvano-molds are very expensive to
manufacture. Amongst other reasons, this is due to the fact that these
forms are frequently impressed with a surface grain, which is supposed to
impress the skin to be manufactured with a leather-type surface grain for
instance.

[0017] Molded foam parts are furthermore frequently coated in so-called
coatings. Such a coating is a protection layer. Without this protection
layer, the surfaces of molded foam parts tend to pale and to become
brittle when exposed to UV-light. The protection layer prevents the
exposure to UV-light for instance by absorbing the UV-light.

[0018] For instance, coatings can be varnishes which are added to foam
molds before the foaming processes and subsequently homogeneously bond
with the foam. After demolding, the foam is then practically covered with
the "coat". The reject rate with molded foam parts covered in coating is
relatively high and can amount to up to 30%. Release agents must also be
used for clean demolding.

[0019] In the manufacture of carpets, such as are used for instance in
vehicle construction, the back side of the carpet--mostly a thermally
preformed carpet--is provided with a relatively thin-walled foam layer.
The aim of this measure is to increase foot comfort, to absorb
tolerances, and to achieve sound insulation. In order to be able to
remove this extensive foam skin from the tool after the reaction time, a
thin-walled foil, which has been thermoformed beforehand, is usually
placed on the corresponding tool side as a release medium and disposed of
after stripping. This process is costly in terms of labor and costs.

[0020] The object of the invention is to improve the prior art.

[0021] The object is solved by a molded insert for a molded part mold,
more specifically a foam mold or galvano-mold, with an upper part and a
corresponding lower part, with a cavity, more specifically a hollow,
wherein the molded part mold creates a shape of a material, more
specifically a foam, that is introduced in the cavity, wherein the molded
insert is adapted to be disposed on the molded part mold so that in the
disposed state, a cavity with a reduced volume is formed and the molded
insert contributes to impressing the material.

[0022] Thus, a speedy exchange of the actual forming cavity can be
ensured.

[0023] Furthermore, by removing the molded insert from the molded part
mold, it is possible to wait for the reaction time to run out while
already manufacturing the next foam part by means of molded inserts newly
introduced into the molded part mold.

[0024] The following terms must be explained:

[0025] The "molded part mold" is a conventionally manufactured molded part
mold, for instance made of aluminum or steel, which is usually used for
manufacturing a molded part. The molded part mold more specifically
includes a "foam part" with an upper part and a corresponding lower part.
Thereby, the upper and lower part can be separated in order to remove a
molded part. Foams which reproduce the shape formed by the upper part and
the lower part can furthermore be injected into the closed foam mold,
thus forming the foam molded part.

[0026] The molded part mold can furthermore be configured as a
galvano-form. The galvano-form can also have an upper part and a
corresponding lower part, only a lower part or an upper part being
usually used. Thin formations such as skins can be manufactured with
galvano-forms. Particularly high quality skins are produced by slightly
etching the galvano-form, so that it has a so-called grain. In this
manner, skins having a leather-type surface structure for instance can be
manufactured.

[0027] The "molded insert" can completely fill the molded part mold or
only cover parts of the molded part mold. Finally, the molded insert can
be a plate or any other substantial object which is demolded together
with the molded part.

[0028] The "cavity" is a hollow space formed by the molded part mold. In
this context, in a one-piece molded part mold, it is more specifically
referred to as "hollow". The cavity and the hollow have in common that
when introducing a material, such as a foam for instance, the form of the
cavity or of the hollow is reproduced by the material.

[0029] The "introduced material" is more specifically a liquid or foamed
material, which forms a solid body through a hardening process. For
instance, the material can be a plastic foam, more specifically a soft,
semi-hard, hard and/or integral foam. Epoxy resins can also be used as
introduced material. Impregnated fibers such as fiber mats impregnated
with epoxy resin (prepregs) which harden in the cavity, can also be
introduced. Powdery materials such as those used in a slush molding
method are also included.

[0030] In this context, "adapted to be disposed" means more specifically
that the molded insert is adapted to the molded part mold in such a
manner that the molded part mold receives the molded insert and that the
molded part to be manufactured can be manufactured by means of the molded
insert. A form-fit disposition is preferred, so that the molded part mold
can act uniformly on the molded insert.

[0031] In order to manufacture molded parts without release agents, a
surface of the molded insert related to the volume reducing cavities can
have a slight or no interfacial tension. The interfacial tension must
thereby be determined by the introduced material as well as the material
of the related surface. The slight interfacial tension applies more
specifically to steel and aluminum which form the surface of a convention
molded part mold.

[0032] Since the quantitative values of the interfacial tension depend on
the system used, which interacts with the surface, it is sufficient if
for this specific system, the above condition is met. More specifically
with the "foam" system, it is important that when the foam is hardened,
the interfacial tension between the hardened foam and the surface of the
molded insert be lower than with aluminum or steel.

[0033] The literature often refers to a surface tension instead of an
interfacial tension. In the following, these terms must considered as
synonyms.

[0034] Since merely the material property of the surface of the molded
insert is significant with regard to being free of a release agent, the
surface of the molded insert related to the volume reducing cavity can be
coated.

[0035] In another embodiment, the surface of the molded insert related to
the volume reducing cavity is formed by a plastic material. Thus,
alternatives in terms of materials to aluminum and steel can be made
available.

[0036] Slight interfacial surface tensions or interfacial tensions can be
achieved by forming the surface of the molded insert related to the
volume reducing cavity with a polyolefin, more specifically with
polyethylene.

[0037] In another embodiment, the molded insert has a temperature
conducting element which is more specifically made of metal. The
temperature gradient of the material in the molded insert relative to the
actual molded part mold made of aluminum or steel for instance, can be
increased or reduced by means of this temperature conducting element.
Thus it is possible to heat the material in the molded insert as well as
to efficiently cool the material in the molded insert. Metals with good
heat conducting properties are preferably used, though other heat
conductors or insulators can also be used.

[0038] In order to also ensure a good temperature conductivity of the
molded insert, the thickness of the material of the molded insert can
amount to between 0.8 mm and 8 mm and most preferably approximately 2.5
mm. It is thereby particularly advantageous for heat conductivity to use
very low material thicknesses.

[0039] In another embodiment the molded insert is manufactured as an
injection molded part. In this manner, molded insert can be manufacture
in great numbers, thus considerably reducing costs.

[0040] In order to ensure a determined fixation and a determined detach of
the molded insert into or from the molded part mold, the molded insert
can have a fastening element which allows a detachable solid assembly in
the molded part mold. More specifically clamping or screwing devices are
possible embodiments of the fastening element.

[0041] In order to give stability to the molded insert, the molded insert
can form a support structure.

[0042] In order to reduce weight or to obtain a determined heat
insulation, the support structure can have hollow spaces.

[0043] In another embodiment, joined partial molded inserts form the
molded insert. More specifically extensive molded inserts such as carpet
coverings in automobiles can thus be manufactured.

[0044] In order to form a molded insert with the partial molded inserts
that is as homogeneous as possible, the partial molded inserts can have
connection elements which can form a stable molded insert. Thereby, the
connection elements can for instance be base on a type of groove and
spring principle. Screw connections with dedicated threads can also be
implemented.

[0045] In another aspect of the invention, the object can be solved by a
method for manufacturing a molded part with a molded part mold with a
cavity which impresses a form onto an introduced material.

Patent applications by Otto Wiesmayer, Neustadt/donau DE

Patent applications in class Foam or porous material containing

Patent applications in all subclasses Foam or porous material containing